Introduces the \ICS macro.

It replaces various occurences of code like
ICS\textit{i}(\tcode{F})
with the more readable and customizable
\ICS{i}{F}
Adds support for listings in footnotes.
Replaced manual newline technique for description lists.

In two descriptions lists of [cpp.predefined], a newline is added manually
after the description text. This requires putting the defined term in the
definition, i.e. outside the optional argument of \item.

This commit replaces this technique to insert a newline by using the
enumitem package and automatic line breaks.
Replaces the bnftab of for-statements with a codeblock.

This is a replacement rule, not a grammatical rule;
compare to the range-based-for-statement and while-statements.
Replaces $\sim$ with \tilde
Adds support for \multirow
Replaces all \textit in [over] and harmonizes usage of \term vs \placeholder
Removes the (visual) definition of postfix-expression from the list of possible function calls.

This is a non-copied bnf environment, and does not indend to define "postfix-expression".
Note it is the only occurence of such a pseudo-/partial definition, and the only occurence
of a manual ':' after the nonterminal which is defined.
Adds a short explanation of how the macros are used.
Removes a superfluous \br from a bnf environment.